Objective: To investigate the chemical compositions of Maxing Shigan Decoction (麻杏石甘汤, MXSGD) and elucidate its anti-influenza A virus (IAV) mechanism from prediction to validation. Methods: Ultra high-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was employed to analyze the chemical compositions of MXSGD. Network pharmacology theories were used to screen and identify shared targets of both the potential targets of active ingredients of MXSGD and IAV. A protein-protein interaction (PPI) network was then constructed, followed by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses. The binding stability between core bioactive compounds and key targets was validated by molecular docking and dynamic simulations. A total of 24 BALB/c mice were infected with IAV to build IAV mouse models. After successful modelling, the mouse models were randomly divided into model, MXSGD high-dose (2.8 g/kg), MXSGD low-dose (1.4 g/kg), and oseltamivir (20.14 mg/kg) groups, with an additional normal mice as control group (n = 6 per group). The treatments were administered by gavage daily between 8:00 a.m. and 10:00 a.m. for five consecutive days. Upon completion of the administration, the body weight ratio, lung index, protein content in the bronchoalveolar lavage fluid (BALF), and the levels of inflammatory factors including interleukin (IL)-6 and tumor necrosis factor (TNF)-α in mice were measured to preliminarily analyze the therapeutic efficacy of MXSGD against IAV infection. Furthermore, the expression levels of mechanistic target of rapamycin (mTOR), hypoxia inducible factor (HIF)-1α, and vascular endothelial growth factor (VEGF) proteins in the HIF-1 signaling pathway, which was enriched by network pharmacology, were detected by Western blot. Results: A total of 212 chemical components in MXSGD were identified by the UPLC-MS/MS method. These chemical components can be classified into 9 primary categories and 31 secondary categories. After intersecting the chemical component targets with IAV-related targets, a total of 567 potential MXSGD components targeting IAV were identified. The construction of PPI network and the results of both GO and KEGG enrichment analyses revealed that the anti-IAV effects of MXSGD were associated with multiple pathways, including apoptosis, TNF, HIF-1, and IL-17 signaling pathways. The results of molecular docking demonstrated that the binding energies between the core compound 1-methoxyphaseollin and key targets including HIF-1α, mTOR, and VEGF were all lower than – 5.0 kcal/mol. Furthermore, molecular dynamics simulations confirmed the structural stability of the resulting complexes. Animal experiments showed that compared with the normal controls, IAV-infected mice showed significantly reduced body weight ratio, markedly increased lung index, protein content in BALF, and the levels of inflammatory factors such as IL-6 and TNF-α (P < 0.01), thereby causing damage to the lung tissue; consequently, the expression levels of mTOR, HIF-1α, and VEGF proteins in the lung tissues of these mice were significantly elevated (P < 0.01). However, after MXSGD treatment, the mouse models presented a significant increase in body weight ratio, as well as marked decreases in lung index, protein content in BALF, and the levels of inflammatory factors including IL-6 and TNF-α (P < 0.01). Furthermore, the therapy alleviated IAV-induced injuries and significantly downregulated the expression levels of mTOR, HIF-1α, and VEGF proteins in lung tissues (P < 0.01 or P < 0.05). Conclusion MXSGD exerts anti-IAV effects through multi-component, multi-target, and multi-pathway synergism. Among them, 1-methoxyphaseollin is identified as a potential key component, which alleviates virus-induced lung injury and inflammatory response via the regulation of HIF-1 signaling pathway, providing experimental evidence for the clinical application of MXSGD.

Objective:To report the nationwide surveillance results of pathogenic profiles and antimicrobial resistance patterns of Gram-positive bloodstream infections in China in 2023.Methods:The clinical isolates of Gram-posttive bacteria from blood cultures were collected in member hospitals of National Bloodstream Infection Bacterial Resistant Investigation Collaborative System（BRICS）during January to December 2023. Antimicrobial susceptibility testing was performed using the dilution method recommended by the Clinical and Laboratory Standards Institute（CLSI）. Statistical analyses were conducted using WHONET 5.6 and SPSS 25.0 software.Results:A total of 4 385 Gram-positive bacterial isolates were obtained from 60 participating center. The top five pathogens were Staphylococcus aureus（ n=1 544，35.2%），coagulase-negative Staphylococci（ n=1 441，32.9%）， Enterococcus faecium（ n=574，13.1%）， Enterococcus faecalis（ n=385，8.8%），and α-hemolytic Streptococci（ n=187，4.3%）. The prevalence of methicillin-resistant Staphylococcus aureus（MRSA）and methicillin-resistant coagulase-negative Staphylococci（MRCNS）was 26.2%（405/1 544）and 69.8%（1 006/1 441），respectively. Notably，all Staphylococci remained susceptible to glycopeptide or daptomycin. Staphylococcus aureus demonstrated excellent susceptibility（>97.0%）to cephalobiol，rifampicin，trimethoprim-sulfamethoxazole，linezolid，minocycline，tigecycline，and eravacycline. No Enterococcus exhibiting resistance to linezolid were detected. Glycopeptide resistance was uncommon but more frequent in Enterococcus faecium（resistance to vancomycin and teicoplanin：both 1.7%）compared to Enterococcus faecalis（both 0.3%）. The detection rates of MRSA and MRCNS exhibited significant regional variations across the country（ χ2=17.674 and 148.650，respectively，both P<0.001）. No vancomycin-resistant Enterococci were detected in central China. Institutional comparison demonstrated higher prevalence of MRSA（ χ2=14.111， P<0.001）and MRCNS（ χ2=4.828， P=0.028）in provincial hospitals than that in municipal hospitals. Socioeconomic analysis identified elevated detection rates of both MRSA（ χ2=18.986， P<0.001）and MRCNS（ χ2=4.477， P=0.034）in less developed regions（per capita GDP

Objective:To report the results of bacterial resistant investigation collaborative system（BRICS）on the distribution and antimicrobial resistance profile of clinical Gram-negative bacteria isolates from bloodstream infections in China in 2023，and provide reference for clinical tretment of bloodstream infections and prevention and control of bacterial resistance.Methods:The clinical isolates of Gram-negative bacteria from blood cultures in member hospitals of BRICS were collected during January 2023 to December 2023. Antibiotic susceptibility tests were conducted by agar dilution or broth dilution methods recommended by Clinical and Laboratory Standards Institute（CLSI）. WHONET 5.6 and SPSS 25.0 were used to analyze the data.Results:During the study period，11 492 strains of Gram-negative bacteria were collected from 60 hospitals，of which 10 098（87.9%）were Enterobacterales and 1 394（12.1%）were non-fermentative bacteria. The top 5 bacterial species were Escherichia coli（50.0%）， Klebsiella pneumoniae（26.1%）， Pseudomonas aeruginosa（5.1%）， Acinetobacter baumannii complex（5.0%）and Enterobacter cloacae complex（4.1%）. The ESBL-producing rates in Escherichia coli， Klebsiella pneumoniae and Proteus mirablilis were 46.8%（2 685/5 741），18.3%（549/2 999）and 44.0%（77/175），respectively. The prevalence of carbapenem-resistant Escherichia coli（CREC）and carbapenem-resistant Klebsiella pneumoniae（CRKP）were 1.3%（76/5 741）and 15.0%（450/2 999）；32.9%（25/76）and 78.0%（351/450）of CREC and CRKP were sensitive to ceftazidime/avibactam combination，respectively. 94.7%（72/76）and 90.2%（406/450）of CREC and CRKP were sensitive to aztreonam/avibactam combination. Furthermore，57.9%（44/76）and 79.1%（356/450）were sensitive to imipenem/relebactam combination. The prevalence of carbapenem-resistant Acinetobacter baumannii（CRAB）complex was 64.6%（370/573），while more than 80.0% of CRAB complex was sensitive to tigecycline，eravacycline and polymyxin B. The prevalence of carbapenem-resistant Pseudomonas aeruginosa（CRPA）was 17.0%（99/581）. There were differences in the composition ratio of Gram-negative bacteria in bloodstream infections and the prevalence of important Gram-negative bacteria resistance among different regions in China，with statistically significant differences in the prevalence of CREC，CRKP，CRPA and CRAB complex（ χ2=10.6，28.6，10.8 and 19.3， P<0.05）. The prevalence of ESBL-producing Escherichia coli， CREC，CRAB complex and CRKP were higher in provincial hospitals than those in municipal hospitals（ χ2=12.5，9.8，12.7 and 57.8，all P<0.01）. Conclusions:Gram-negative bacteria are the main pathogens causing bloodstream infections in China，and Escherichia coli is ranked in the top，while the trend of Klebsiella pneumoniae increases continuously with time. CRKP infection shows a slow upward trend，CREC infecton maintains a low prevalence level，and CRAB complex infection continues to exhibit a high prevalence rate. The composition and resistance patterns of pathogens causing bloodstream infections vary to some extent across different regions and levels of hospitals in China.

Objective:To investigate the efficacy of rigid ureteroscopic laser lithotripsy combined with N-trap(RULL+N-trap),which is scoop-shaped,in the treatment of ureteral stones with a maximum diameter ≥1.5 cm.Methods:This retrospective cohort study included patients diagnosed with ureteral calculi who underwent rigid ureteroscopic lithotripsy(RULL)combined with N-Trap stone entrapment system at the Department of Urology,Peking University Third Hospital,by the same surgical team between June 2021 and September 2024.A total of 364 patients were initially enrolled.After excluding 21 patients due to missing critical outcome variables,two distinct cohorts were established:38 patients with ureteral stones measuring ≥1.5 cm in maximum diameter,and 305 patients with stones＜1.5 cm in maximum diameter.To minimize selection bias and control for confounding variables,propensity score matching(PSM)was employed.This resulted in two well-balanced groups:31 patients with stones 1.5 cm in maximum diameter and 31 patients with stones＜1.5 cm in maximum diameter,matched on baseline demographic and clinical characteristics.The primary outcomes assessed between the two groups included stone clearance.Secondary outcomes included changes in renal function indicators,specifically serum creatinine(SCr)and estimated glomerular filtration rate(GFR),and other factors like postopera-tive hospital stay and operative time.Results:In the matched cohort,the patients with stones ≥1.5 cm in maximum diameter had significantly longer operative time compared with those with smaller stones:(85.8±28.8)min vs.(62.4±24.6)min(P＜0.05).Postoperative length of hospital stay showed no significant difference:(2.26±1.79)d vs.(2.03±0.80)d(P＞0.05).The stone clearance on postoperative day one was 90.3％in the study group vs.100.0％in the control group(P＞0.05).One month postoperatively,the stone clearance was 93.5％vs.100.0％,respectively(P＞0.05).Changes in SCr were(-6.58±16.10)μmol/L vs.(-13.70±12.50)μmol/L,and changes in GFR were(5.92±14.90)mL/(min·1.73 m2)vs.(7.47±11.20)m L/(min·1.73 m2),with no statistically significant differences observed between the two groups for either renal function marker(P＞0.05).Conclusion:Ureteroscopic lithotripsy combined with N-trap is an optional method for treating ureteral stones with a maximum diameter ≥1.5 cm.The overall therapeutic efficacy is comparable,with the added benefit of significantly reducing the economic burden on patients.

Objective:To investigate the efficacy of rigid ureteroscopic laser lithotripsy combined with N-trap(RULL+N-trap),which is scoop-shaped,in the treatment of ureteral stones with a maximum diameter ≥1.5 cm.Methods:This retrospective cohort study included patients diagnosed with ureteral calculi who underwent rigid ureteroscopic lithotripsy(RULL)combined with N-Trap stone entrapment system at the Department of Urology,Peking University Third Hospital,by the same surgical team between June 2021 and September 2024.A total of 364 patients were initially enrolled.After excluding 21 patients due to missing critical outcome variables,two distinct cohorts were established:38 patients with ureteral stones measuring ≥1.5 cm in maximum diameter,and 305 patients with stones＜1.5 cm in maximum diameter.To minimize selection bias and control for confounding variables,propensity score matching(PSM)was employed.This resulted in two well-balanced groups:31 patients with stones 1.5 cm in maximum diameter and 31 patients with stones＜1.5 cm in maximum diameter,matched on baseline demographic and clinical characteristics.The primary outcomes assessed between the two groups included stone clearance.Secondary outcomes included changes in renal function indicators,specifically serum creatinine(SCr)and estimated glomerular filtration rate(GFR),and other factors like postopera-tive hospital stay and operative time.Results:In the matched cohort,the patients with stones ≥1.5 cm in maximum diameter had significantly longer operative time compared with those with smaller stones:(85.8±28.8)min vs.(62.4±24.6)min(P＜0.05).Postoperative length of hospital stay showed no significant difference:(2.26±1.79)d vs.(2.03±0.80)d(P＞0.05).The stone clearance on postoperative day one was 90.3％in the study group vs.100.0％in the control group(P＞0.05).One month postoperatively,the stone clearance was 93.5％vs.100.0％,respectively(P＞0.05).Changes in SCr were(-6.58±16.10)μmol/L vs.(-13.70±12.50)μmol/L,and changes in GFR were(5.92±14.90)mL/(min·1.73 m2)vs.(7.47±11.20)m L/(min·1.73 m2),with no statistically significant differences observed between the two groups for either renal function marker(P＞0.05).Conclusion:Ureteroscopic lithotripsy combined with N-trap is an optional method for treating ureteral stones with a maximum diameter ≥1.5 cm.The overall therapeutic efficacy is comparable,with the added benefit of significantly reducing the economic burden on patients.

Objective:To examine the effect of antidepressant treatment on the longitudinal depressive burden in patients with bipolar depression.Methods:Subjects were recruited from a national multicenter, naturalistic observational project: Comprehensive Assessment and Follow-up Descriptive Study on Bipolar Disorder study (CAFE-BD). A total of 110 patients with bipolar depression (51 males, 59 females; aged 18-64 years, mean age 34.4±11.1 years) were consecutively enrolled between January 2012 and December 2013 from outpatients and inpatients of nine medical institutions, including six psychiatric hospitals and three general hospitals. Based on the use of antidepressants as defined in this study, patients were classified into a medicated group (Ads, n=74) and a non-medicated group (nAds, n=36). Diagnosis of bipolar depression was confirmed using the MINI (Chinese version), and baseline and follow-up assessments were conducted using the Assessment of Mood Disorders Evaluation (ADE) and the Clinical Monitoring Form (CMF). Depression burden indicators, including aggregate depression scores (SUM-D), number of depressive symptoms (NUM-D), and total depression burden, were compared between the Ads group and nAds group at mid-term (the 6 th month) and endpoint (the 12 nd month). Longitudinal changes in these indicators were also analyzed. Results:The proportion of bipolar depressive patients on antidepressants was 67% (74/110). Among them, 85% (63/74) were taking antidepressants at baseline; this dropped to 76% (56/74) at mid-term, and 64% (47/74) at the endpoint. SUM-D were higher in the Ads group than in the nAds group at baseline (9 (6.5, 11) vs 7.38 (5.5, 9.0); W=1 712.00, P=0.015), and there was no statistically significant difference in NUM-D and total depressive burden between two groups at any time points ( P>0.05). Compared to baseline, the Ads group had significantly lower SUM-D (0.5 (0, 1), 1.33 (0.5, 2.5) vs. 9 (6.5, 11); W=2 770.00, 2 743.00), NUM-D (0 (0, 0), 0 (0, 1) vs. 7 (5, 8); W=2 621.00, 2 601.50) and total depressive burden (c 2=64.36, 59.00) at both mid-term and endpoint (all P<0.001); While SUM-D (0.59 (0.4, 0.7), 1 (0.8, 2.5) vs. 7.38 (5.5, 9.0); W=664.50, W=666.00), NUM-D (0 (0, 0), 0 (0, 1) vs. 6 (4, 7); W=527.00, 528.00) and total depression burden ( χ 2=31.00, 31.00) in the nAds group were also significantly decreased at both mid-term and endpoint (all P<0.001). There were no statistically significant differences in the changes in depression burden indicators between the two groups from baseline to mid-follow-up or endpoint, nor from mid-follow-up to endpoint ( P>0.05). Conclusion:In a 12-month real-world naturalistic follow-up study, both medicated and non-medicated bipolar depression groups experienced significant and similar reductions in depression burden.

Objective:To examine the effect of antidepressant treatment on the longitudinal depressive burden in patients with bipolar depression.Methods:Subjects were recruited from a national multicenter, naturalistic observational project: Comprehensive Assessment and Follow-up Descriptive Study on Bipolar Disorder study (CAFE-BD). A total of 110 patients with bipolar depression (51 males, 59 females; aged 18-64 years, mean age 34.4±11.1 years) were consecutively enrolled between January 2012 and December 2013 from outpatients and inpatients of nine medical institutions, including six psychiatric hospitals and three general hospitals. Based on the use of antidepressants as defined in this study, patients were classified into a medicated group (Ads, n=74) and a non-medicated group (nAds, n=36). Diagnosis of bipolar depression was confirmed using the MINI (Chinese version), and baseline and follow-up assessments were conducted using the Assessment of Mood Disorders Evaluation (ADE) and the Clinical Monitoring Form (CMF). Depression burden indicators, including aggregate depression scores (SUM-D), number of depressive symptoms (NUM-D), and total depression burden, were compared between the Ads group and nAds group at mid-term (the 6 th month) and endpoint (the 12 nd month). Longitudinal changes in these indicators were also analyzed. Results:The proportion of bipolar depressive patients on antidepressants was 67% (74/110). Among them, 85% (63/74) were taking antidepressants at baseline; this dropped to 76% (56/74) at mid-term, and 64% (47/74) at the endpoint. SUM-D were higher in the Ads group than in the nAds group at baseline (9 (6.5, 11) vs 7.38 (5.5, 9.0); W=1 712.00, P=0.015), and there was no statistically significant difference in NUM-D and total depressive burden between two groups at any time points ( P>0.05). Compared to baseline, the Ads group had significantly lower SUM-D (0.5 (0, 1), 1.33 (0.5, 2.5) vs. 9 (6.5, 11); W=2 770.00, 2 743.00), NUM-D (0 (0, 0), 0 (0, 1) vs. 7 (5, 8); W=2 621.00, 2 601.50) and total depressive burden (c 2=64.36, 59.00) at both mid-term and endpoint (all P<0.001); While SUM-D (0.59 (0.4, 0.7), 1 (0.8, 2.5) vs. 7.38 (5.5, 9.0); W=664.50, W=666.00), NUM-D (0 (0, 0), 0 (0, 1) vs. 6 (4, 7); W=527.00, 528.00) and total depression burden ( χ 2=31.00, 31.00) in the nAds group were also significantly decreased at both mid-term and endpoint (all P<0.001). There were no statistically significant differences in the changes in depression burden indicators between the two groups from baseline to mid-follow-up or endpoint, nor from mid-follow-up to endpoint ( P>0.05). Conclusion:In a 12-month real-world naturalistic follow-up study, both medicated and non-medicated bipolar depression groups experienced significant and similar reductions in depression burden.

Objective:To report the nationwide surveillance results of pathogenic profiles and antimicrobial resistance patterns of Gram-positive bloodstream infections in China in 2023.Methods:The clinical isolates of Gram-posttive bacteria from blood cultures were collected in member hospitals of National Bloodstream Infection Bacterial Resistant Investigation Collaborative System（BRICS）during January to December 2023. Antimicrobial susceptibility testing was performed using the dilution method recommended by the Clinical and Laboratory Standards Institute（CLSI）. Statistical analyses were conducted using WHONET 5.6 and SPSS 25.0 software.Results:A total of 4 385 Gram-positive bacterial isolates were obtained from 60 participating center. The top five pathogens were Staphylococcus aureus（ n=1 544，35.2%），coagulase-negative Staphylococci（ n=1 441，32.9%）， Enterococcus faecium（ n=574，13.1%）， Enterococcus faecalis（ n=385，8.8%），and α-hemolytic Streptococci（ n=187，4.3%）. The prevalence of methicillin-resistant Staphylococcus aureus（MRSA）and methicillin-resistant coagulase-negative Staphylococci（MRCNS）was 26.2%（405/1 544）and 69.8%（1 006/1 441），respectively. Notably，all Staphylococci remained susceptible to glycopeptide or daptomycin. Staphylococcus aureus demonstrated excellent susceptibility（>97.0%）to cephalobiol，rifampicin，trimethoprim-sulfamethoxazole，linezolid，minocycline，tigecycline，and eravacycline. No Enterococcus exhibiting resistance to linezolid were detected. Glycopeptide resistance was uncommon but more frequent in Enterococcus faecium（resistance to vancomycin and teicoplanin：both 1.7%）compared to Enterococcus faecalis（both 0.3%）. The detection rates of MRSA and MRCNS exhibited significant regional variations across the country（ χ2=17.674 and 148.650，respectively，both P<0.001）. No vancomycin-resistant Enterococci were detected in central China. Institutional comparison demonstrated higher prevalence of MRSA（ χ2=14.111， P<0.001）and MRCNS（ χ2=4.828， P=0.028）in provincial hospitals than that in municipal hospitals. Socioeconomic analysis identified elevated detection rates of both MRSA（ χ2=18.986， P<0.001）and MRCNS（ χ2=4.477， P=0.034）in less developed regions（per capita GDP

Objective:To report the results of bacterial resistant investigation collaborative system（BRICS）on the distribution and antimicrobial resistance profile of clinical Gram-negative bacteria isolates from bloodstream infections in China in 2023，and provide reference for clinical tretment of bloodstream infections and prevention and control of bacterial resistance.Methods:The clinical isolates of Gram-negative bacteria from blood cultures in member hospitals of BRICS were collected during January 2023 to December 2023. Antibiotic susceptibility tests were conducted by agar dilution or broth dilution methods recommended by Clinical and Laboratory Standards Institute（CLSI）. WHONET 5.6 and SPSS 25.0 were used to analyze the data.Results:During the study period，11 492 strains of Gram-negative bacteria were collected from 60 hospitals，of which 10 098（87.9%）were Enterobacterales and 1 394（12.1%）were non-fermentative bacteria. The top 5 bacterial species were Escherichia coli（50.0%）， Klebsiella pneumoniae（26.1%）， Pseudomonas aeruginosa（5.1%）， Acinetobacter baumannii complex（5.0%）and Enterobacter cloacae complex（4.1%）. The ESBL-producing rates in Escherichia coli， Klebsiella pneumoniae and Proteus mirablilis were 46.8%（2 685/5 741），18.3%（549/2 999）and 44.0%（77/175），respectively. The prevalence of carbapenem-resistant Escherichia coli（CREC）and carbapenem-resistant Klebsiella pneumoniae（CRKP）were 1.3%（76/5 741）and 15.0%（450/2 999）；32.9%（25/76）and 78.0%（351/450）of CREC and CRKP were sensitive to ceftazidime/avibactam combination，respectively. 94.7%（72/76）and 90.2%（406/450）of CREC and CRKP were sensitive to aztreonam/avibactam combination. Furthermore，57.9%（44/76）and 79.1%（356/450）were sensitive to imipenem/relebactam combination. The prevalence of carbapenem-resistant Acinetobacter baumannii（CRAB）complex was 64.6%（370/573），while more than 80.0% of CRAB complex was sensitive to tigecycline，eravacycline and polymyxin B. The prevalence of carbapenem-resistant Pseudomonas aeruginosa（CRPA）was 17.0%（99/581）. There were differences in the composition ratio of Gram-negative bacteria in bloodstream infections and the prevalence of important Gram-negative bacteria resistance among different regions in China，with statistically significant differences in the prevalence of CREC，CRKP，CRPA and CRAB complex（ χ2=10.6，28.6，10.8 and 19.3， P<0.05）. The prevalence of ESBL-producing Escherichia coli， CREC，CRAB complex and CRKP were higher in provincial hospitals than those in municipal hospitals（ χ2=12.5，9.8，12.7 and 57.8，all P<0.01）. Conclusions:Gram-negative bacteria are the main pathogens causing bloodstream infections in China，and Escherichia coli is ranked in the top，while the trend of Klebsiella pneumoniae increases continuously with time. CRKP infection shows a slow upward trend，CREC infecton maintains a low prevalence level，and CRAB complex infection continues to exhibit a high prevalence rate. The composition and resistance patterns of pathogens causing bloodstream infections vary to some extent across different regions and levels of hospitals in China.

Objective:To report the results of national surveillance on the distribution and antimicrobial resistance profile of clinical Gram-negative bacteria isolates from bloodstream infections in China in 2022.Methods:The clinical isolates of Gram-negative bacteria from blood cultures in member hospitals of national bloodstream infection Bacterial Resistant Investigation Collaborative System（BRICS）were collected during January 2022 to December 2022. Antibiotic susceptibility tests were conducted by agar dilution or broth dilution methods recommended by Clinical and Laboratory Standards Institute（CLSI）. WHONET 5.6 and SPSS 25.0 software were used to analyze the data.Results:During the study period，9 035 strains of Gram-negative bacteria were collected from 51 hospitals，of which 7 895（87.4%）were Enterobacteriaceae and 1 140（12.6%）were non-fermenting bacteria. The top 5 bacterial species were Escherichia coli（ n=4 510，49.9%）， Klebsiella pneumoniae（ n=2 340，25.9%）， Pseudomonas aeruginosa（ n=534，5.9%）， Acinetobacter baumannii complex（ n=405，4.5%）and Enterobacter cloacae（ n=327，3.6%）. The ESBLs-producing rates in Escherichia coli， Klebsiella pneumoniae and Proteus spp. were 47.1%（2 095/4 452），21.0%（427/2 033）and 41.1%（58/141），respectively. The prevalence of carbapenem-resistant Escherichia coli（CREC）and carbapenem-resistant Klebsiella pneumoniae（CRKP）were 1.3%（58/4 510）and 13.1%（307/2 340）；62.1%（36/58）and 9.8%（30/307）of CREC and CRKP were resistant to ceftazidime/avibactam combination，respectively. The prevalence of carbapenem-resistant Acinetobacter baumannii（CRAB）complex was 59.5%（241/405），while less than 5% of Acinetobacter baumannii complex was resistant to tigecycline and polymyxin B. The prevalence of carbapenem-resistant Pseudomonas aeruginosa（CRPA）was 18.4%（98/534）. There were differences in the composition ratio of Gram-negative bacteria in bloodstream infections and the prevalence of main Gram-negative bacteria resistance among different regions，with statistically significant differences in the prevalence of CRKP and CRPA（ χ2=20.489 and 20.252， P<0.001）. The prevalence of CREC，CRKP，CRPA，CRAB，ESBLs-producing Escherichia coli and Klebsiella pneumoniae were higher in provinicial hospitals than those in municipal hospitals（ χ2=11.953，81.183，10.404，5.915，12.415 and 6.459， P<0.01 or <0.05），while the prevalence of CRPA was higher in economically developed regions（per capita GDP ≥ 92 059 Yuan）than that in economically less-developed regions（per capita GDP <92 059 Yuan）（ χ2=6.240， P=0.012）. Conclusions:The proportion of Gram-negative bacteria in bloodstream infections shows an increasing trend，and Escherichia coli is ranked in the top，while the trend of CRKP decreases continuously with time. Decreasing trends are noted in ESBLs-producing Escherichia coli and Klebsiella pneumoniae. Low prevalence of carbapenem resistance in Escherichia coli and high prevalence in CRAB complex have been observed. The composition ratio and antibacterial spectrum of bloodstream infections in different regions of China are slightly different，and the proportion of main drug resistant bacteria in provincial hospitals is higher than those in municipal hospitals.